Researchers have developed a groundbreaking terahertz biosensor utilizing electromagnetically induced transparency (EIT) metamaterials and gold nanoparticles (AuNPs) to significantly improve the detection sensitivity of biomolecules, particularly histidine. This advancement addresses the limitations faced by traditional terahertz spectroscopy methods, which often struggle to detect biomolecules due to weak changes in their dielectric properties at low concentrations.
Terahertz spectroscopy has garnered considerable attention for its potential applications in biomedical detection and sensing because of its low energy requirements and high sensitivity to specific biomolecular vibrational modes. While certain biomolecules can be identified within the terahertz range, their small sizes often limit effective interactions with terahertz waves, which complicates high-sensitivity detection.
To tackle these limitations, the newly developed biosensor incorporates two EIT metamaterials enhanced with AuNPs. This integration is driven by the electrostatic interaction between AuNPs and positively charged biomolecules, leading to localized field enhancements at the interfaces between biomolecules and metamaterials. This innovation achieves up to threefold increases in detection sensitivity, enabling intuitive differentiation between histidine, which is positively charged, and glucose, which is neutral and showed less pronounced response enhancement.
Histidine, as an amino acid, is particularly significant due to its roles across various biological processes. The electrostatic attraction between carboxyl-modified AuNPs and histidine molecules paves the way for enriching this biomolecule at the metamaterial surface, enhancing detection capabilities. Research findings indicate this dielectric property response is pivotal, with modulation depth (MD) and modulation enhancement (ME) factors correlatively demonstrating significant improvements for histidine at the EIT peak frequency, underscoring the sensor’s potential for substantial biomolecular analysis.
Experimental protocols involved crystallizing biomolecular solutions of histidine and glucose, both with and without AuNPs, on the metamaterial surface. Results indicated significant differences; for histidine, the response sensitivity demonstrated linear relationships with concentrations, offering clearer detection pathways compared to glucose solutions.
Researchers have also validated the sensor’s multiparameter imaging capabilities, visualizing concentration and spatial distribution of biomolecules through improvements at both EIT1 and EIT2 peaks, demonstrating the sensor’s practical applications for complex biological analysis.
The work signifies more than just enhanced detection; it showcases new strategies for high-sensitivity biosensing platforms and opens avenues for high-throughput biomolecular analysis, highlighting the importance of integrating nanotechnology with advanced materials science. Robust mechanisms such as these are poised to revolutionize diagnostic imaging and biomolecular assessments across various biomedical applications.